vinyl-transform

This module lets you take your standard text transform streams from npm,
(e.g. envify), and use them in a
vinyl pipeline. It'll transparently take care of
handling both buffered and streaming vinyl instances for you too.

Creates a vinyl transform stream. transformFn(filename) is a function which
takes the file's path and returns a text transform stream. If you've used
browserify's
transform API
you'll recognise this pattern: it's effectively the same API used here.